Air purification system

ABSTRACT

This invention relates to an air purification apparatuses and methods for air purification. The air purification apparatuses pass air through energy beams that form one or more fields of energy within a chamber to produce an outflow of sterilized air. In some aspects, a charge generation system is implemented to repel particles from the chamber walls. In some aspects, the fields of energy extend across substantially an entirety of the cross sectional area of the interior volume of the chamber and longitudinally within the chamber. In some aspects, a controller is configured to rotate a beam of collimated light energy within the chamber at a rotational velocity corresponding to at least V/W, wherein V is the linear velocity of a particle within the chamber along the longitudinal axis, and W is the width of the beam of collimated light energy.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 14/340,912 filed 25 Jul. 2014, which is acontinuation of and claims priority to U.S. patent application Ser. No.13/830,158 filed 14 Mar. 2013, which claims priority to U.S. ProvisionalPatent Application No. 61/613,776 filed 21 Mar. 2012 under the sametitle. This application is also related to U.S. patent application Ser.No. 13/249,035 filed 29 Sep. 2011, now issued U.S. Pat. No. 8,319,195,which is a continuation of U.S. patent application Ser. No. 11/302,179filed 12 Dec. 2005, which is a continuation-in-part application thatclaims priority benefit of International Application PCT/US2004/018772filed on 14 Jun. 2004, designating the United States, which claimspriority benefits to U.S. Provisional Patent Application No. 60/478,231,filed 12 Jun. 2003 and U.S. patent application Ser. No. 10/640,477 filed11 Aug. 2003. The entire disclosures of the aforementioned documents arehereby incorporated herein by reference.

BACKGROUND Field

This application relates generally to an air purification apparatus andmethods of air purification.

Description of the Related Art

Air circulation and purification systems are directed to the removal ofairborne particulates from the air. Airborne particulates comprise acomplex mixture of organic and inorganic substances, bacteria, virusesand any other substances that are small enough to become suspended inthe air and atmosphere. Exposure to airborne particulates poses dangersto humans and other organisms because particulates may, for example,induce allergic reactions or cause sickness. The respiratory system isthe major route of entry for airborne particulates. The deposition ofparticulates in different parts of the human respiratory system dependson particle size, shape, density, and individual breathing patterns.

Air circulation systems, for example, air conditioning and heatingsystems in buildings, aircraft, vessels and vehicles, have been known tocirculate airborne viruses and bacteria, which can spread sickness tothe occupants. Some air circulation systems in buildings, aircraft, andautomobiles use physical filters to trap dust and other particulates.However, physical filters do not to trap small particulates, forexample, viruses and spores. Additionally, physical filters can becomeclogged which in turn decreases air flow, increasing facility costs.Also, the accumulation of particulates on physical filters requiresregular cleaning or replacement of the filter, which can interrupt airflow and can be expensive. In some systems, air is purified orsterilized by irradiating the circulating air with ultraviolet lights.One drawback of this method is that dust and particulates collect on theemission source which reduces the intensity of the ultraviolet light.Over time, this collection of particulates reduces the effectiveness ofthe purification process. Additionally, ultraviolet systems must slowthe air to gain more energy to pathogen exposure time to be effective.Slowing the air, as filters also do, significantly increases energyexpenses. Therefore, it is desirable to provide a cost effective andefficient means of sterilizing large volumes of air.

The purification of air and objects has been a common requirement fornumerous types of practices and environments. For example, sterilizedair and objects are required for hospital surgical rooms. The practiceof dentistry usually does not require a sterile environment, but it doesrequire the use of sterile dental tools. The state of the art disclosesvarious devices and methods for achieving these objectives. However, theprior art tool sterilization systems may not provide adequatesterilization, or may have similar limitations as those described abovegenerally for air purification systems.

Additionally, recent world developments and increased concern overbiological weapons and viruses, such as the SARS virus, or a. nigerspores, has created a need for simple apparatuses that provide a safehaven by destroying biological pathogens as well as aerosols andsuspended particulates. Conventional technology is directed primarilytowards filtration methods for removing the above-noted micro objects.However, filtration has its limits described above: efficiency, cost,size, etc.

SUMMARY

The apparatuses, methods and devices of this disclosure each haveseveral innovative aspects, no single one of which is solely responsiblefor the desirable attributes disclosed herein.

One innovative aspect of the subject matter described in this disclosurecan be implemented in an air purification apparatus. The airpurification apparatus includes a chamber comprising one or more wallsforming an interior volume, wherein at least one of the walls comprisesa reflective surface facing inwardly towards the interior volume. Theair purification apparatus includes a collimated light source configuredto direct a beam of collimated light energy into the chamber. The airpurification apparatus includes a charge generation system configured toimpart a charge to the one or more walls, to repel particles containedwithin the interior volume from the one or more walls.

Another innovative aspect of the subject matter described in thisdisclosure can be implemented in an air purification apparatus. The airpurification apparatus includes a chamber comprising one or moresidewalls forming an inner cross-sectional area extended longitudinallyalong a longitudinal axis to form an interior volume. Each sidewallincludes an inwardly-facing reflective surface. The air purificationapparatus includes a collimated light source configured to direct a beamof collimated light into the chamber. The air purification apparatusincludes a beam redirector disposed within the interior volume andconfigured to rotate through a complete revolution about a rotationalaxis such that the beam of collimated light energy is redirected to forma field of collimated light energy extending across substantially anentirety of the cross sectional area of the interior volume andextending longitudinally along the longitudinal axis.

Another innovative aspect of the subject matter described in thisdisclosure can be implemented in an air purification apparatus. The airpurification apparatus includes a chamber. The chamber includes one ormore sidewalls forming an interior volume. The one or more sidewallsinclude one or more surfaces facing inwardly towards the interiorvolume. The chamber includes a first opening and a second openingconfigured to allow air to flow through the interior volume from thefirst opening to the second opening along a longitudinal axis. The airpurification apparatus includes a collimated light source configured todirect a beam of collimated light energy into the interior volume of thechamber. The air purification apparatus includes a beam redirectordisposed within the interior volume and configured to rotate through acomplete revolution about a rotational axis such that the beam ofcollimated light energy is redirected to form a field of collimatedlight energy extending across substantially an entirety of a crosssectional area of the interior volume during said revolution. The airpurification apparatus includes a controller configured to rotate thebeam redirector about the rotational axis at a rotational velocitycorresponding to at least V/W, wherein V is the linear velocity of aparticle within the chamber along the longitudinal axis, and W is thewidth of the beam of collimated light energy.

Details of one or more implementations of the subject matter describedin this specification are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages will becomeapparent from the description, the drawings, and the claims. Note thatthe relative dimensions of the following figures may not be drawn toscale.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of an embodiment of an airsterilization apparatus with a cleaning system.

FIG. 2 is a front perspective view of an embodiment of an airsterilization apparatus with a rotating beam redirector.

FIG. 3A is a front view of the air sterilization apparatus of FIG. 2.

FIG. 3B is a detailed view of the rotating beam redirector shown in FIG.3A.

FIG. 3C is another front view of the air sterilization apparatus shownin FIG. 2.

FIG. 3D is a side cross-sectional view of the air sterilizationapparatus shown in FIG. 2.

FIG. 4A is a side perspective cross-sectional view of an embodiment of achamber with a field of collimated light energy extending across aninner cross sectional area of the chamber and longitudinally within thechamber.

FIG. 4B is a side cross-sectional view of an embodiment of a chamberwith a portion of a reflective surface that is oriented to besubstantially non-parallel with a longitudinal axis extending throughthe chamber.

FIG. 4C is a detailed view of the reflective surface shown in FIG. 4B.

FIGS. 5A and 5B are side and front views, respectively, of an embodimentof an air sterilization apparatus configured to form a field of energyextending across an inner cross sectional area of the chamber andlongitudinally within the chamber.

FIGS. 6A and 6B are side and front cross-sectional views, respectively,of another embodiment of an air sterilization apparatus configured toform a field of energy extending across an inner cross sectional area ofthe chamber and longitudinally within the chamber.

FIGS. 7A and 7B are top cross-sectional views of other embodiments of anair sterilization apparatus configured to form a field of energyextending across an inner cross sectional area of the chamber andlongitudinally within the chamber.

FIG. 8A is a side cross-sectional view of an embodiment of an airsterilization apparatus configured to sterilize objects within achamber.

FIG. 8B is a side cross-sectional view of another embodiment of an airsterilization apparatus configured to sterilize objects within achamber.

FIG. 8C is a side cross-sectional view of an embodiment of an airsterilization apparatus that includes a plurality of the sterilizationchambers shown in FIG. 8B.

FIG. 9 is a side schematic view of another embodiment of an airsterilization apparatus.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

This application is directed to methods and apparatus for purificationof air and objects by directing a beam of energy from an energy sourceinto a chamber. Some embodiments use light energy of proscribedfrequencies (wavelengths), energy densities and durations. Someembodiments use a cleaning system that repels particles from a wall ofthe chamber, to allow the particles to be impacted by the beam ofenergy, and to keep the reflective surfaces, if any, within the chamberclean. Some embodiments include a beam redirector that rotates an energybeam to form a field of collimated light energy extending across a crosssectional area of an interior volume of the chamber and extendinglongitudinally within the chamber. Some embodiments include a controllerconfigured to rotate a beam redirector within the chamber at arotational velocity corresponding to at least V/W, wherein V is thelinear velocity of a particle within the chamber, and W is the width ofthe beam of collimated light energy. Each of these embodiments increasethe likelihood of particulate within the chamber being impacted, andthus destroyed, by the beam of energy, or the energy field created bysweeping the beam through the chamber. The duration and frequency of theenergy exposure to the particulate depends, in part, upon the residencyperiod of objects within the volume, the intensity and/or energy densityof the energy, the frequency or frequencies of the energy, the flow ofair through the chamber, and other variables that will be described inmore detail below.

Examples of possible particulates suspended in an air flow includebacteria, viruses, toxic gases, toxic molecules, and any other harmfulparticles. Exposure to a singular energy field within the chamber, ormultiple energy fields within the ventilation chamber, destroys andneutralizes spores, bacteria, viruses, protozoa, eukaryotes, otherorganics, and other particulates. The size of the particulates may varygreatly, however substantially all of the particulates, regardless oftheir size are irradiated by at least one energy field. In someembodiments, 100% of all the particulates, regardless of size, travelingthrough the air purification apparatus collide with at least one energyfield before exiting the chamber. In other embodiments, 99.8% of all theparticulates traveling through the air purification apparatus collidewith at least one energy field before exiting the chamber. In yet otherembodiments, 99.98% of all the particulates traveling through the airpurification apparatus collide with at least one energy field beforeexiting the chamber. In yet other embodiments, 99.99% of all theparticulates traveling through the air purification apparatus collidewith at least one energy field before exiting the chamber.

The air purification apparatuses described herein can be integrated intovehicle platforms such as land vehicles, water craft, underwater craft,and aircraft. For example, the system can be configured to beimplemented within surface ships and submarines, for example, during abio attack on a naval fleet. These vehicle platforms are chosen due totheir intrinsically controlled internal environment. Using an aircraftplatform as an example, the air purification apparatus can be placedpreferably downstream of any air conditioning packs that may be presenton the aircraft, and close to the external air intake(s). The airpurification apparatuses can be located in the central recirculationplenum or at a singular exit from that plenum so all returned air issterilized. Recirculated air in conventional aircraft systems is onlyHEPA filtered. The chamber inlet end and outlet end are operativecoupled to the main air flow such that all air to be delivered to theinterior areas of the aircraft, e.g., cabin and cockpit, may passthrough the air purification apparatus. Power for the apparatus can beobtained from the aircraft power harness, taking into account obviousrequirements for voltage and load matching. Upon activation of the airpurification apparatus, all air being delivered to the interior areas ofthe aircraft may be subjected to purification. Moreover, ifintelligently integrated into the aircraft environmental controls,recirculated air can also be subjected to re-purification therebyaddressing issues of contamination originating from within the interiorareas of the aircraft. Similar integration approaches can be taken withrespect to other vehicle platforms.

In certain embodiments of this series, the air purification apparatuscan be portable, e.g., not integrated with or part of a permanent orsemi-permanent structure (non-deployable assets). In these embodiments,the apparatus may further comprise an air handler, e.g., a blower havingan air displacement element and a motor, and the outlet of the chamberis adapted to fluidly couple with a portable structure such as acontainer or other transportable rigid structure, or couple witherectable structures such as hazardous materials tents, field medicaltents and related medical temporary structures, neonatal care tents,burn recovery tents, and other inflatable tents. Preferably, either typeof structure is relatively sealable from an external environment wherebythe apparatus provides sterilized air to the interior of the structureand further creates/maintains some level of positive pressure within thestructure relative to the environment's atmospheric pressure adjacent tothe structure, thus minimizing the undesirable ingress of unconditionedair. The apparatus can be discrete from the structure whereby only aduct or similar air transport conduit is used to operative link theapparatus to the structure, or the apparatus can be integrated with thestructure whereby the outlet of the chamber is directly exposed to theinterior space of the structure. The optional air handler can be locatedeither upstream or downstream of the apparatus, depending upon designconsiderations. The air purification systems described herein, such asthe portable systems, can be used within the ventilation systems ofbuildings, vehicles, etc., or can be implemented discretely, forexample, to purify a single room or enclosure.

With respect to portable air purification apparatus, it may be desirableto have the apparatus operate off grid. In these embodiments, theapparatus further comprises a power source. The power source maycomprise a power generator utilizing an internal or external combustionengine to provide mechanical energy to a suitable electrical generator,the power source may be a battery (rechargeable or not), or the powersource may be a fuel cell. For critical applications such as military orfirst responder environments, fuel cells provide a convenient andreliable means for providing the necessary power to operate even highpower lasers and optionally air handlers.

FIG. 1 is a front perspective view of an embodiment of an airsterilization apparatus 100 with a cleaning system 30. Cleaning system30 can be implemented with any of the air sterilization apparatusdescribed herein. Additionally, “air sterilization apparatus” and “airpurification apparatus” are used synonymously herein. Apparatus 100 caninclude a chamber 10 and a source of energy 20 configured to directenergy into the chamber 10. The energy directed into the chamber 10 candestroy particles within chamber 10, such as stationary particles, orparticles flowing through chamber 10.

Chamber 10 can be linear or curvilinear, and/or can have both linear andcurvilinear portions. For example, a first end 15 of the chamber 10 canbe perpendicular with respect to a second end 13 of the chamber 10. Thedegree of curvature of the chamber 10, and the angle between first end15 and second end 13 may cover any possible range. For example, the end15 to the chamber 10 can be oriented approximately 45 degrees from thesecond end 13 of the ventilation duct.

The chamber 10 can comprise one or more sidewalls 12 that form aninterior volume 14. In some embodiments, sidewalls 12 can comprise asheet metal or other thin material, similar to the ductwork within aventilation system. However, it will be understood that sidewalls 12 cancomprise any structure that forms the interior volume 14. For example,sidewalls 12 can comprise a portion of a housing, manifold, block, orother structure. For example, sidewalls 12 can comprise a portion of alarger support structure in or on which the other components of chamber10 are supported or contained.

The interior volume 14 of chamber 10 can have various cross-sectionalshapes, such as the square-shape shown, to form a square duct. Theinterior volume 14 can have a round cross-sectional shape, to form acylindrical duct, or any other regular or irregular cross-sectionalshape suitable to form an interior volume when extended longitudinallyalong a longitudinal axis 900. It will be understood that longitudinalaxis 900 follows the general shape of interior volume 14, and is notnecessarily straight. For example, the chamber 10 can form a curvilinearduct, in which the longitudinal axis 900 follows the same curvilinearshape longitudinally within the duct. Generally, the ends 13, 15 caninclude openings 13A, 15A, configured to attach to a ventilation systemand allow air to flow through the interior volume 14 along thelongitudinal axis 900, such that chamber 10 forms a portion of aventilation duct. However, in some embodiments, the chamber 10 can be asubstantially closed chamber, wherein ends 13, 15 include additionalsidewalls to cover openings 13A, 15A. For example, chamber 10 can beconfigured to be used as a sterilization apparatus for medicalequipment.

The energy source 20 can comprise a collimated light source, such as alaser or other source of non-ionizing collimated electromagneticradiation capable of directing a beam of collimated light energy 22towards a target volume, and irradiating the volume. The energy source20 can comprise any other type of energy source capable of directing abeam of energy into a volume, having a power output sufficient forachieving the intended purpose of the apparatus and methods. Energysource 20 can provide a beam of sufficient strength to destroy orneutralize one or more of dust particles, pollen, pathogens, allergens,gasses, or other particulates that are present in the flow of airthrough the system. The energy source 20 may be of the continuous waveor pulsed type, with many embodiments employing a pulsed type forreasons well known to those skilled in the art. Depending upon theenergy density for a given application, a 10 watt CO₂ laser emittingradiation in the infrared region may be sufficient and higher powerand/or additional lasers may be employed. In some embodiments a 15 wattlaser is used, and in still other embodiments a 60 watt laser is used.In an embodiment, the wavelength of the laser or energy of the emittedbeam(s) is selected based upon the target species identified forneutralization. For example, in some embodiments a wavelength rangingbetween approximately 1056 and 1064 microns (μm) provided benefits inneutralizing certain species, such as spores of Aspergillus niger.

The energy source 20 can be positioned outside the chamber 10, and thebeam 22 can be directed through one or more openings 18 extendingthrough sidewall 12. The opening 18 can include a transparent opticalwindow or other structure to prevent contamination into chamber 10through opening 18. The optical window may or may not be used toredirect at least on beam through sidewall 12. The optical window may beplaced along any portion of the chamber 10. One having skill in the artmay vary the placement of the optical window to optimize exposure of theenergy field to the inside of the chamber 10.

The optical window may be constructed out of any suitable material knownto those having skill in the art. In an embodiment, the optical windowcomprises a material that allows at least one beam 22 of energy to passfrom the outside of the chamber 10 to the inside of the chamber 10. Inanother embodiment, the optical window comprises a material that allowsfor substantially all of the collimated light energy to pass through theoutside of the optical window and into the chamber.

At least one of sidewalls 12 can include a reflective surface 16, toreflect the beam 22 within chamber 10. In some embodiments, each ofsidewalls 12 includes a reflective surface 16, to repeatedly reflect andredirect the beam 22 within chamber 10. Other embodiments describedherein provide additional ways to further reflect and redirect the beam22 within chamber 10.

Surface 16 may be curvilinear, rectilinear or any combination thereof.Furthermore, a portion or the entire interior surface 16 may havevarious characteristics including highly reflective properties, surfaceundulations (linear or curvilinear) or features to assist in beamscattering or intended beam redirection. Moreover, the interior surfacemay be rigid or flexible. If flexible, the surface may be acted upon bya force (mechanical, electrical or pneumatic) to cause deflectionthereof. In certain embodiments, the deflection is cyclical andcharacterized as a vibration.

The reflective surface 16 can be any layer, coating, or other structuresuitable to reflect an energy beam such as a collimated light source.For example, the reflective surface 16 can comprise a reflective metal,such as gold, aluminum, silver, or nickel, reflective polymers, or othersuitably reflective materials. The one or more reflective inner walls ofthe chamber 10 can reflect the beam 22 so that air passing through thechamber 10 passes through multiple beams or fields of energy. One havingskill in the art may increase or decrease the length of the chamber 10to increase or decrease the number of fields or beams through which airmust pass before exiting the chamber 10.

Cleaning system 30 can be configured to repel particles contained withinthe inner volume 14 from the sidewalls 12, to prevent particles fromsettling on and accumulating on sidewalls 12. Particles that settle onsidewalls 12 may provide a focal point for beam 22 on reflective surface16, causing overheating and decreasing the reflective functionality ofsurface 16. In some situations, particle accumulation on sidewall 12 maycause beam 22 to burn a hole through sidewall 12, causing systemcontamination. To repel particles from the sidewalls 12, cleaning system30 can comprise a charge generation system configured to impart a chargeon one or more of sidewalls 12, for example, to surface 16. The chargecan be provided at a similar polarity as the particles within chamber10. For example, it has been observed that particles flowing within aventilation system may naturally form a charge, such as a negativecharge. Thus, charge generation system 30 can employ a similar charge tosidewalls 12 as the particles, such as a negative charge, to repel theparticles as described. In some embodiments, a charge generation systemcan be employed to actively charge the particles, in addition to theaforementioned natural charge that may be formed. For example, a screen,nodes, or other structure can be extended across or from the interior ofchamber 10, and the screen or nodes can be charged with another chargegeneration system, to impart the same charge to particles passingthrough the screen or node field, prior to contacting and beingdestroyed by beam 22. Such active charge to the particles can furtherprevent particle accumulation on sidewalls 12 when sidewalls 12 aresimilarly charged by charge generation system 30. Charge generationsystem 30 can comprise any suitable power source, such as battery,electrode, or other related electronic components, capable of placing acharge on sidewalls 12. Cleaning system 30 is very different fromconventional ventilation cleaning systems, in which the goal was toattract particles to a device mounted on a sidewall, such as a filter oradhesive, etc., rather than repelling them, and allowing them tocontinue to flow within the ductwork being decontaminated. The sidewallcharge may be provided by redirected waste thermal energy formed withinapparatus 100, or within a system within which apparatus 100 isimplemented.

FIG. 2 is a front perspective view of an embodiment of an airsterilization apparatus 200 with a rotating beam redirector 50. FIG. 3Ais a front view of the air sterilization apparatus 200 of FIG. 2. FIG.3B is a detailed view of the rotating beam redirector 200 shown in FIG.3A. FIG. 3C is another front view of the air sterilization apparatus 200shown in FIG. 2. FIG. 3D is a side cross-sectional view of the airsterilization apparatus 200 shown in FIG. 2.

Referring to FIGS. 2-3D, beam redirector 50 can comprise an opticalelement 52 configured to rotate about a rotating axis 901. The opticalelement 52 can rotate through a complete revolution about the axis 901,and in some embodiments, through multiple complete revolutions. Suchrotation can be provided, for example, through a motor 60, a motor shaft54, and an optical element shaft 55. Any other structure suitable toimpart rotational motion on beam redirector 50 about axis 901 can beimplemented, such as other rotational actuators and the like. Opticalelement 52 can comprise any suitable structure configured to redirectthe beam 22 within volume 14 of chamber 10, such as one or more suitablyreflective (e.g., planar) surfaces 56. In some embodiments, opticalelement 52 can comprise other reflective, refractive, transmissive, orother structures, that can redirect a beam of light energy. In someembodiments, optical element 52 can redirect a beam of light energy bydispersing (e.g., bisecting) a single beam, such as a laser beam, intotwo or more beams. In some embodiments, optical element 52 can changethe direction of a beam of light energy by changing the wave velocity ofthe beam.

The rotation of optical element 52 can allow beam 22 to be redirected atvarious incident angles within chamber 10, as illustrated schematicallyby the beams 22A-22F in FIG. 3A. Through said rotation, optical element52 can reflect and sweep beam 22 around the inner perimeter of chamber10, and form a field of energy 80 (FIG. 3D) that extends across thecross sectional area of the interior volume 14. The energy field 80 willincrease the likelihood of contact between particulate matter travelingthrough chamber 10 and the energy within chamber 10 provided by energysource 20, thus increasing the sterilization effects within chamber. Thefield 80 can extend at an angle that is substantially orthogonalrelative to the axis 900, or can be at an angle thereto. In someembodiments, the field 80 can comprise an approximately two-dimensionalshape, for example, when the beams 22A-22F, and the other reflectivebeams forming the field 80, are co-planar. The embodiments of apparatus200 shown in FIGS. 2-3D can produce a field of energy 80 that isapproximately two-dimensional. Alternatively, the field can comprise athree-dimensional shape, when it comprises a plurality of reflectivebeams that also extend longitudinally along axis 900, as describedfurther below.

In use, air enters the chamber 10 through the opening 13A, and passesthrough energy field 80. As the air passes through energy field 80, anyparticles suspended in the air, are irradiated. Energy field 80 isgenerally of sufficient strength to neutralize the particulates. Oncethe air exits the chamber 10 through the opening 15A, the air issubstantially sterile.

Referring to FIG. 3B, a vortex 23 can be formed within a portion ofvolume 14 in which the field of energy 80 formed by the reflected androtated beam 22 may not reach. For example, vortex 23 can be formedwithin portions of volume 14 that are positioned behind optical element52 relative to the collimated light source 20. Thus, particleslongitudinally moving through chamber 10 may not be contacted withinvortex 23 by beam 22, and thus, may not be destroyed, by beam 22. Thewidth shown of beam 22 in FIG. 3B is for illustrative purposes only, andto demonstrate how vortex 23 can be formed.

Referring to FIG. 3C, to increase the likelihood of contact between areflection of beam 22 and a particulate within vortex 23, at least onesidewall 12 of chamber 10 can include the reflective surface 16. In suchan embodiment, beam 22 can initially be redirected by beam redirector 50towards surface 16, as depicted by beam 22G, and then reflected on thesidewall surface 16, to form beam 22H. Beam 22H can cross vortex 23, andthus can increase the likelihood of contact between beam 22 andparticulate within vortex 23. As such, a field of energy 80 can extendacross substantially an entirety of the cross sectional area of theinterior volume 14, and contact (and destroy) an increased percentage ofparticles passing therethrough. Vortex 23 can be crossed and impacted bythe energy beam when the field of energy is reflected longitudinallydown the chamber, as described further herein, and shown in theembodiments of FIGS. 4A-7B.

Referring again to FIG. 2, a controller 70 can be employed to controlvarious parameters of the energy source 20, motor 60 (or otherrotational device), and cleaning system 30. Controller 70 may controlthe polarity, frequency, amplitude, or other parameters of the chargeimparted by cleaning system 30 to portions of the chamber 10. Controller70 can control the flow velocity of the air through the chamber 10,through control of air flow devices, such as fans, pumps, valves, orother devices. Controller 70 may control various characteristics of theenergy source 20, such as the amplitude, frequency, wavelength, width(e.g., diameter), or other characteristics. Controller 70 may pulse orotherwise vary when beam 22 is emitted from the energy source 20. Forexample, to prevent errant reflection, controller 70 may interfaces withenergy source 20 to switch it on and off in synchronicity with theoperation of beam redirector 50. Controller 70 can comprise a personalcomputer, or any other hardware, firmware, software, and the likesuitable to control a system such as apparatus 100.

In some embodiments, controller 70 may control the speed of the rotationof the beam redirector 50. For example, controller 70 may control thespeed of rotation of the beam redirector 50 based upon the linear speedof a particle within the chamber 10, and the width of the beam 22, toincrease the likelihood that the beam 22 would contact (e.g., destroy)the particle within the field of energy created during a single rotationof the beam redirector. As such, controller 70 can be configured torotate configured to rotate the beam redirector 50 about the rotationalaxis 901 at a rotational velocity w corresponding to V/W, wherein V isthe linear velocity of a particle within the chamber along thelongitudinal axis 900, and W is the width (e.g., diameter) of the beamof collimated light energy. Examples 1 and 2 below provide furtherdetails on this relationship and method of controlling beam redirector50 with controller 70. Controller 70 can be employed within any of theair purification apparatuses described herein.

FIG. 4A is a side perspective cross-sectional view of another embodimentof an air sterilization apparatus 300 with a field of energy 80extending across an inner cross sectional area of a chamber 10A andlongitudinally within the chamber 10A.

Chamber 10A can be similar to chamber 10 in FIGS. 1-3D, and is shownwith a cylindrical sidewall 12A for illustrative purposes only; chamber10A and sidewall 12A can comprise other shapes. Sidewall 12A can includethe reflective surface 16. A laser 20 and beam redirector 50A are shownschematically; beam redirector 50A can be similar to beam redirector 50or the other beam redirectors described herein. Beam redirector 50A canbe configured to redirect beam 22 from laser 20 to form an energy field80. Energy field 80 can be similar to that formed by beam redirector 50and redirected beams 22A-22H in FIGS. 2-3D. In this embodiment, the beamredirector 50A can be configured to direct beam 22 both radiallyoutwardly and longitudinally with respect to axis 900, such that energyfield 80 is a three dimensional energy field. For example, energy field80 can comprise a first portion 81 that extends both radially outwardlyand longitudinally with respect to axis 900, until forming a secondportion 82 that contacts and forms a perimeter along an inner surface ofsidewall 12A. A three-dimensional energy field with a controlled shapesuch as energy field 80 can increase the likelihood that any particulatetraveling through volume 14 will be contacted by a portion of the energybeam 20 that forms field 80. The three-dimensional energy field cancomprise a number of different shapes, depending on the configuration ofthe chamber, its sidewalls, and the beam director. In the illustratedembodiment, energy field 80 is approximately frustro-conically shaped.

In embodiments with reflective surface 16, energy field 80 can then bereflected off reflective surface 16 and repeated, radially andlongitudinally along axis 900 down the interior volume 14 of chamber10A, to form one or more additional reflected energy fields 80A, 80B,80C. The reflective angle of the beams impacting and reflecting fromsurface 16 are shown as angle θ₁. Such repeated, reflected,three-dimensional energy fields further increase the likelihood that anyparticulate traveling through volume 14 will be contacted by a portionof the energy beam 20 that forms fields 80A, 80B, 80C, etc.Additionally, any particulate that is not destroyed through an initialcontact with energy field 80, will have an increased likelihood ofsubsequently being destroyed by one of the subsequent, reflected energyfields. In some embodiments, the length of the chamber is adjusted sothat air flowing through the chamber passes through five differentfields of light energy before exiting the chamber. In anotherembodiment, the length of the chamber is adjusted so that air flowingthrough the chamber passes through four different fields of light energybefore exiting the chamber. In another embodiment, the length of thechamber is adjusted so that air flowing through the chamber passesthrough three different fields of light energy before exiting thechamber. In another embodiment, the length of the chamber is adjusted sothat air flowing through the chamber passes through two different fieldsof light energy before exiting the chamber. In another embodiments, asmany as 19 different fields of light energy can be reflected within thechamber, and more or less fields are within the scope of the invention.

Embodiments of the air ventilation systems described herein can includean energy abatement device positioned within the chamber to limit thetravel of the energy beams or fields produced by the energy sourcewithin the chamber. For example, the energy abatement device can preventa portion of the energy field from exiting the chamber of the airventilation system and traveling within the ventilation system to whichthe chamber is attached. Any suitable material known to one having skillin the art as being capable of absorbing beam energy may be used for theenergy abatement device, and/or the energy abatement device may belocated along any portion of an interior of the chamber.

An example of an energy abatement device 11 is illustrated in FIG. 4A.Energy abatement device 11 can form an annular ring-like shape thatextends around an inner perimeter or circumference of sidewall 12A.Other shapes can be used, depending on the shape of the chamber. One ormore energy abatement devices can be employed, and the devices can bepositioned at various locations within the chamber. For example, one ormore energy abatement devices can be located at or near either or bothof ends 13, 15. In some embodiments, the energy abatement device can befitted with one or more heat sinks. Any suitable heat sink known tothose having skill in the art may be used. The heat sink may be furtherconnected to device that further dissipates or redirects the heat energyabsorbed by the heat sink. It will be understood that energy abatementdevice 11, or other suitable devices, can be employed within any of thechambers and air purification apparatuses described herein.

In some embodiments, one or more light baffles can be extended acrossthe inner volume of the chambers described herein. The baffles canpermit air flow thereby but occlude any direct or indirect beam fromexiting the chamber. The baffles can be constructed from any suitablematerial that absorbs and/or reflects beam energy. If the baffles absorbthe energy, it may also be desirable to include means for cooling thebaffles if the air flow rate is insufficient for the task. Examples ofembodiments of light baffles that can be implemented within the airpurification apparatuses described herein are disclosed in U.S. Pat. No.8,319,195, entitled “Methods and Apparatus for Sterilization of Air andObjects” and issued Nov. 27, 2012, the entire contents of which areincorporated herein by reference.

In some embodiments of the air purification apparatuses describedherein, a safety mechanism can be employed to disable energy source 20,and prevent injury, such as retina damage to a person. For example, ashock (e.g., earthquake) sensor can be connected to energy source 20 (orits related controller) that deactivates energy source 20 in the eventthat it is subjected to shock above a threshold. A secure light box orsimilar device can be employed to prevent tampering with the airflowapparatuses described herein, and accidental exposure to energy emittedfrom energy source 20.

FIG. 4B is a side cross-sectional view of an embodiment of a chamber 10Bwith a portion of the reflective surface that is oriented to besubstantially non-parallel with a longitudinal axis extending throughthe chamber 10B. FIG. 4C is a detailed view of the reflective surfaceshown in FIG. 4B.

Referring to FIG. 4C, the reflective surface 16 can include a firstportion 16A that extends generally along and parallel with alongitudinal axis 900A. The longitudinal axis 900A extends approximatelylongitudinally within chamber 10B, similar to axis 900 (FIG. 4B), but isshown radially offset from the center of volume 14.

The reflective surface 16 can include a second portion 16B oriented tobe substantially non-parallel with the longitudinal axis 900A. Thedepth, width, angle, or number of reflective portions 16B may beadjusted to redirect the path of the fields of energy 80 within chamber10B. For example, portion 16B can allow the entry angle θ₁ of energyfield 80, defined as the angle between energy field 80 and axis 900A,can be less than the exit angle θ₂ of energy field 80, defined as theangle between the reflected energy field 80A and axis 900A. Suchreduction between angle θ₁ and θ₂ can decrease the total length Lconsumed by the repeated, reflected energy fields within chamber 10B,and thus decreasing the size of air sterilization apparatus within whichchamber 10B is implemented.

The second portion 16B can have any of a number of differentconfigurations. For example, the second portion 16B can extend aroundsome, or substantially the entirety of an inner perimeter of chamber10B. Second portion 16B can protrude from, or can be recessed withrespect to first portion 16A of reflective surface 16. A recessedportion 16B can reduce flow restrictions within chamber 10B. In someembodiments, second portion 16B comprises a groove that is recessedwithin reflective surface 16. It will be understood that the secondportion 16B can be implemented within other chambers and other airpurification apparatuses described herein.

In some embodiments, both the length of the chamber and the depth,width, and number of angled reflective portions are configured so thatair passing through the ventilation chamber must pass through at leastfive, four, three, or two fields of energy before exiting theventilation chamber.

It will be understood that both the two and three dimensional energyfields described herein can be formed within various shapes and sizes ofchambers, at various orientations within the chambers, and can be formedwith various embodiments of beam redirectors. Additional embodiments ofair sterilization apparatus that can form energy fields are shown inFIGS. 5A-10C.

FIGS. 5A and 5B are side and front views, respectively, of an embodimentof an air sterilization apparatus 400 configured to form athree-dimensional field of energy 80 extending across an inner crosssectional area of a chamber 10B and longitudinally within the chamber10B. Apparatus 400 comprises a beam redirector 50B configured to formenergy field 80 within chamber 10B. Beam redirector 50B can comprise anoptical element 52A configured to rotate about an axis, similar tooptical element 52 in FIGS. 2-3D. Element 52A can rotate about arotating axis that is approximately collinear with axis 900, or offsetfrom axis 900. Optical element 52A can be configured to redirect beam 22from energy source 20 similar to, and can be similarly configured asoptical element 52 (FIGS. 2-3D). In some embodiments, optical element52A can implement a lens that redirects the beam 22 through refractioninstead of or in addition to reflection. The resulting shape of field 80can be similar as those other embodiments described herein. Ends 13 and15 of chamber 10B can be oriented at an angle with respect to eachother, such that chamber 10B forms an elbow. Beam redirector 50B canpositioned within the elbow, and can be positioned internally withinchamber 10B (within volume 14) or externally to chamber 10B.

FIGS. 6A and 6B are side and front cross-sectional views, respectively,of another embodiment of an air sterilization apparatus 500 configuredto form a three-dimensional field of energy 80 extending across an innercross sectional area of a chamber 10C and longitudinally within thechamber 10C. Apparatus 500 can include a beam redirector 50C andrefractive optical element 52A, similar to beam redirector 50B andoptical element 52A shown in FIGS. 5A and 5B. In this embodiment, thebeam redirector 50C can be mounted within volume 14, and can bepositioned within bent portion of chamber 10C, such as an elbow, orwithin a substantially straight portion of chamber 10C. A support member24 can extend from sidewall 12 into chamber volume 14 to provide supportto beam redirector 50C. Support member 24 can include an inner channel25 through which the energy beam 22 can be directed from energy source20. The energy beam 22 can be directed through optical element 52A bydirecting beam 22 in a first direction (e.g., downwardly as shown) fromenergy source 20, and then reflected off a reflective element 53 in asecond direction (e.g., horizontally as shown) through optical element52A. Optical element 52A can be rotated about rotational axis 901 toform energy field 80. Optical element 52A can be rotated by a motor 60and driveshaft 51 mounted on support member 24, or through othersuitable rotational devices and components. Support member 24 can extendfrom a single side 12 of chamber 10C, or can extend from a first side toa second side, to provide additional support and stability to componentsmounted thereon. An aerodynamic element 26 can be provided on a portionor all of the upstream and/or downstream side of support member 24, toreduce the drag on the air being ventilated through chamber 10C.

FIGS. 7A and 7B are top cross-sectional views of other embodiments of anair sterilization apparatus 600 and 700, respectively. Apparatuses 600and 700 can include the energy source 20 and beam redirector 50, andmany other similar components as apparatus 100 shown in FIGS. 2-3D.Apparatuses 600 and 700 can be configured such that beam 22 from energysource 20 and the axis of rotation 901 of optical element 52 aresubstantially non-collinear. Such positioning can form an angle θ₃between beam 22 and axis 901 that is greater than zero degrees, and lessthan 90 degrees. Such embodiments can allow beam 22 to reflect offsurface 56 of optical element 52, and travel longitudinally down innervolume 14, to form energy field 80, and in some embodiments, form one ormore reflected energy fields 80A, etc. The angle θ₃ between beam 22 andaxis 901 can be varied, for example, by positioning energy source 20(and thus beam 22) at a substantially non-orthogonal angle relative tosidewalls 12 (FIG. 7A), or positioning beam redirector 50 such that axis901 is at a non-orthogonal angle relative to sidewalls 12.

In some embodiments, one or more objects other than air can be placedwithin the chambers of the air sterilization apparatuses describedherein. Such embodiments can allow for one or more objects such asmedical tools and the like, placed within the chambers of the apparatusto be sterilized.

FIG. 8A is a side cross-sectional view of an embodiment of an airsterilization apparatus 910 configured to sterilize one or more objectswithin a chamber 10D. Chamber 10D can include a base 12B and a cover 12Cto cover ends 15, 13, respectively, of chamber 10D. As such, chamber 10Dcan form a substantially enclosed interior volume 14. A rotating beamredirector 50D can be configured to direct beam 22 through opening 18and form a plurality of energy fields 180A-180C, which can reflect offsurface 16, and form reflected fields 80A-80C, which can impact and thussterilize a tool 90 positioned on base 12B. Additionally, the thermalenergy from surfaces directly impacted by the energy fields can flow viaconduction over non-directly energy impacted surfaces, to furtherachieve sterilization. In some embodiments, the optical element 52A canbe configured to rotate in the X-plane, and/or oscillate around axis900, to provide the energy fields and reflected fields shown. In someembodiments, the optical element 52A can be configured to move in theY-plane while the aforementioned X-plane rotation/oscillation isongoing.

FIG. 8B is a side cross-sectional view of another embodiment of an airsterilization apparatus 1000 configured to sterilize one or more objectswithin a chamber 10E. Chamber 10E can be a substantially enclosedchamber, as shown in FIG. 8A. In this embodiment, a rotating beamredirector 50E can be configured to direct beam 22 through opening 18,and form a plurality of energy fields 280A-280C, which can reflect offsurface 16, and form reflected fields 80A-80E, which can impact and thussterilize the tool 90 positioned on the base 12B. In some embodiments,one or more chambers can be rotated through energy fields, so that theentirety of the outer surface of the tool is impacted with energy andsterilized.

FIG. 8C is a side cross-sectional view of an embodiment of an airsterilization apparatus 1100 that includes a plurality of thesterilization chambers 10E shown in FIG. 8B. Air sterilization apparatus1100 can include a plurality of stations in a conveyor, carousel orother suitable movable multi-platform manufacturing configuration, toallow a plurality of tools 90 in a plurality of sterilization chambers10E, to be sterilized consecutively by air sterilization apparatus 1000.

FIG. 9 is a side schematic view of another embodiment of an airsterilization apparatus 1200. Apparatus 1200 can include an outerhousing 1210, which can support and enclose an air sterilization system400A that is similar to system 400 shown in FIGS. 5A-5B. A difference isthat apparatus 1200 can include the inner channel 25 to route energybeam 22 from energy source 20 to the optical element 52A of beamredirector 50B. One or more reflective elements can be positioned withininner channel 25, to direct energy beam 22 therethrough. For example,the energy beam 22 can be directed (e.g., horizontally) through a first(e.g. horizontal) section 25A of channel 25, and change direction (e.g.,vertically) after reflecting off a first reflective element 53A. Beam 22can then be directed (e.g., vertically) through a second (e.g.,vertical) section 25B of channel 25, and change direction (e.g.,horizontally) after reflecting off a second reflective element 53B. Beam22 can then be directed (e.g., horizontally) through a third (e.g.,horizontal) section 25C of channel 25, to optic element 52A. In thisway, beam 22 can be directed into beam redirector 50B in an orientationapproximately opposite to the direction of beam 22 from energy source20. Beam 22 can then pass through optic element 52A, which can berotated to form energy field 80, similar to apparatus 400 (FIGS. 5A-5B).By including reflective elements 53A and 53B, and allowing for theredirection of energy beam 22 prior to it being further redirected bybeam redirector 50B, energy source 20 can be oriented in a way that canreduce the overall space envelope of apparatus 1200. Such embodimentscan allow for a compact, portable air sterilization apparatus that canbe employed within confined spaces, such as windows, doors, walls, orother openings within, for example, a dwelling or vehicle, such as anaircraft. It will be understood that one or more reflective elementssimilar to elements 53A and 53B in FIG. 9, can be employed with any ofthe embodiments described herein, to allow for various positionings ofenergy source 20 and to orient the reflective beam 22 from the energysource 20 in different ways.

Some embodiments of the present application relate to a method ofpurifying or sterilizing air. In an embodiment, the air purificationmethod comprises flowing air into an interior volume of a chamber;directing a beam of collimated light energy into the chamber; andimparting a charge to one or more walls of the chamber to repelparticles within the interior volume from one or more sidewalls of thechamber. Some embodiments further include reflecting the beam ofcollimated light energy off at least one sidewall. Imparting a chargecan include imparting a negative charge. Some embodiments furtherinclude imparting a similar charge to particles within the interiorvolume of the chamber.

In another embodiment, the air purification method comprises directing abeam of collimated light energy into an interior volume of a chamber;rotating the beam of collimated light energy within the interior volumeabout a rotational axis; and redirecting the beam of collimated lightenergy to form a field of collimated light energy extending acrosssubstantially an entirety of a cross sectional area of the interiorvolume and extending longitudinally along a longitudinal axis within theinterior volume. Some embodiments further comprise flowing air throughan opening into the interior volume, and from the interior volumethrough a second opening. Some embodiments further comprise reflectingthe field of collimated light energy to form a reflected field ofcollimated light energy extending across substantially an entirety of across sectional area of the interior volume and extending longitudinallyalong a longitudinal axis within the interior volume.

In another embodiment, the air purification method comprises directing abeam of collimated light energy of width W into an interior volume of achamber; and rotating the beam of collimated light energy within theinterior volume about a rotational axis at a rotational velocitycorresponding to at least V/W, wherein V is the linear velocity of aparticle within the chamber along the longitudinal axis. Someembodiments further comprise adjusting the linear velocity of theparticle within the chamber by adjusting the amount of airflow throughthe chamber. In some embodiments, rotating comprises rotating the beamof collimated light energy a complete revolution about a rotational axissuch that the beam of collimated light energy is redirected to form afield of collimated light energy extending across substantially anentirety of a cross sectional area of the interior volume during saidrevolution. In some embodiments, rotating further comprises extendingthe field of collimated light energy longitudinally along thelongitudinal axis. Some embodiments further comprise adjusting thewavelength of the beam of collimated light energy

As described above, the speed of the rotation of the rotating opticalelement within embodiments of the air sterilization apparatus describedherein may be adjusted via any method known to those having skill in theart, including adjustment via the controller. The below examplesillustrate that the speed of the rotation of the optical element can beconfigured so that the energy field impacts approximately 100% of anyparticles traveling in the airstream.

Example 1: Cylindrical Ventilation Duct

This example discusses how the field of laser energy impacts anincreased portion, such as up to approximately 100% of the particulatesin a ventilation airstream traveling through a cylindrical ventilationduct, such as the embodiment shown with respect to FIGS. 4A-6B.

Those having skill in the art recognize that ventilation systems aregenerally constructed to contain a laminar air flow. Laminar air flowrequires a Reynolds Number (N_(R)) that is less than 3,000. An N_(R)above 3,000 will result in turbulent flow. Note: the change from laminarto turbulent flow can be reached at N_(R)=2,000 and as low asN_(R)=1,000.

For this example, we will select the highest N_(R) that still describesa laminar flow: 3,000. We select the worst case scenario parameters forthe example to demonstrate functionality in the extreme and thus alsothe norm.

The Reynolds Number (N_(R)) is given by:

$N_{R} = {{\frac{d\; \rho \; V}{n}\text{~~~=>}\mspace{14mu} V} = \frac{N_{R}n}{d\; \rho}}$

Where: d=diameter of vent (meters)

$\rho = {{density}\mspace{14mu} {of}\mspace{14mu} {air}\mspace{14mu} \left( \frac{kg}{m^{3}} \right)}$

$V = {{linear}\mspace{14mu} {air}\mspace{14mu} {flow}\mspace{14mu} {rate}\mspace{14mu} {within}\mspace{14mu} {vent}\mspace{14mu} \left( \frac{meters}{second} \right)}$

n=viscosity of air (pascals×second)

For example purposes, the following assumption will be made:

The temperature of air within the vent is T=20° C.=68° F.

By definition, at 20° C. the density of air is

$\rho = {1.204\mspace{14mu} \frac{kg}{m^{3}}}$

and the viscosity of air is n=0.018 m Pas=0.018×10⁻³ Pas=0.000018 Pas.

As we determined earlier the linear air flow rate is given by:

$V = \frac{N_{R}n}{d\; \rho}$

Therefore, for N_(R)=3,000

$V_{3,000} = {\frac{3000 \times 0.018 \times 10^{- 3}{Pas}}{0.2032\mspace{14mu} m \times 1.204\mspace{14mu} {{kg}/m^{3}}} = {\frac{0.054\frac{{kg} \times s}{s^{2} \times m}}{0.2447\frac{kg}{m^{2}}} = {0.221\mspace{14mu} m\text{/}s \times 1\mspace{14mu} {{ft}/0.3048}\mspace{14mu} m}}}$

Thus, the maximum possible laminar air flow rate within the vent yieldsa particle linear speed of:

V ₃₀₀₀=0.724 ft/sec=0.221 m/s

Our example will continue by setting a revolution per minute (RPM) forthe refractive window that is equivalent to the time it takes adimensionless particle (so used to negate a limitation of the system bynanometer sized particles) to travel a distance equivalent to the widthof the laser beam. This will ensure that each particulate is impacted bythe laser at least once, in a single rotation of the optical element,which forms a single energy field. In addition, reflections of theenergy field down the reflective vent will generate further impacts forany remaining particles not completely destroyed by a single impact withthe laser beam.

For this example, a laser beam of width 2 mm will be used.

The time that it takes a particulate to travel the width of this laserbeam is:

$T = {\frac{D}{V} = {\frac{2\mspace{14mu} {mm}}{0.724\mspace{14mu} {{ft}/\sec}} = {\frac{2 \times 10^{- 3}\mspace{14mu} m}{0.221\mspace{14mu} {m/\sec}} = {0.00905\mspace{14mu} \sec}}}}$

Now, from the time that the particulate travels the width of the beam,the optical element must rotate the beam once around the circumferenceof the vent. Doing so will increase the likelihood of any particulatepassing through the “laser field” without being hit by the laser beam;as mentioned above. The optical element must therefore rotate at avelocity (v) of:

$v = {\frac{D}{T} = {\frac{circumference}{0.00905\mspace{14mu} \sec} = {\frac{2\; \pi \; r}{0.00905\mspace{14mu} \sec} = {\frac{0.6387\mspace{14mu} m}{0.00905\mspace{14mu} \sec} = {70.57\mspace{14mu} m\text{/}s}}}}}$

Continuing unit's yields:

v=70.57 meter/sec×rev/0.6387 meter×60 sec/min=6,629 rev/min (rpm)

Thus, for the maximum airflow that will be found in any laminarventilation system, the field of laser energy created using a 2 mm beamin an 8 inch diameter ventilation duct with a refractive window that isrotating at 7,000 rpm will impact approximately 100% of particulate.

Following this same example, a 1 mm beam in an 8 inch diameter chamberrotated at approximately 12,600 rpm will impact approximately 100% ofparticulate.

Also, following this example a chamber with a 6 ft diameter and a 1 mmbeam will yield

V₃₀₀₀=0.0245 m/s

T=0.04078 seconds

V=140.886 m/s=>V=1,471.31 rpm

Example 2: Square Ventilation Duct

This example discusses how the field of laser energy achieves anincreased impact of approximately 100% of particulate in a ventilationairstream, for example, in a square chamber, such as that shown in FIGS.2-3D. Additional test results provided elsewhere herein describe howenough energy can be imparted through each laser/particle impact to killeach biological molecule impacted.

Those familiar with the art recognize that ventilation systems areconstructed to contain a laminar air flow. Laminar air flow requires aReynolds Number (N_(R)) that is less than 3,000. An N_(R) above 3,000will result in turbulent flow. Note: the change from laminar toturbulent flow can be reached at N_(R)=2,000 and as low as N_(R)=1,000.

For this example, we will select the highest N_(R) that still describesa laminar flow: 3,000. We select the worst case scenario parameters forthe example to demonstrate functionality in the extreme and thus alsothe norm.

The Reynolds Number (N_(R)) for a square duct is given by:

$N_{R} = {\frac{\rho \; V\; D_{H}}{n} = {{\frac{\rho \; V\; L}{n}\text{~~~=>}\mspace{14mu} V} = \frac{N_{R}n}{L\; \rho}}}$

Where: v=linear mean velocity (meters/seconds)

$\rho = {{density}\mspace{14mu} {of}\mspace{14mu} {air}\mspace{14mu} \left( \frac{kg}{m^{3}} \right)}$

n=viscosity of air (pascals×second)

D_(H)=Hydraulic diameter=L=length of square vent

For example purposes, the following assumption will be made:

The temperature of air within the vent is T=20° C.=68° F.

By definition, at 20° C. the density of air is

$\rho = {1.204\mspace{14mu} \frac{kg}{m^{3}}}$

and the viscosity of air is n=0.018 m Pas=0.018×10⁻³ Pas=0.000018 Pas.

$V = \frac{N_{R}n}{L\; \rho}$

As we determined earlier the linear air flow rate is given by:

Therefore, for N_(R)=3,000

$V_{3,000} = {\frac{3000 \times 0.018 \times 10^{- 3}{Pas}}{0.3048\mspace{14mu} m \times 1.204\mspace{14mu} {{kg}/m^{3}}} = {\frac{0.054\frac{{kg} \times s}{s^{2} \times m}}{0.36698\frac{kg}{m^{2}}} = {{0.147\mspace{14mu} m\text{/}s \times 1\mspace{14mu} {{ft}/0.3048}\mspace{14mu} m} = {0.483\mspace{14mu} {{ft}/s}}}}}$

Thus, the maximum possible laminar air flow rate within the vent yieldsa particle linear speed of:

V ₃₀₀₀=0.483 ft/sec=0.147 m/sec

Our example will continue by setting a revolution per minute (RPM) forthe reflective plate that is equivalent to the time it takes adimensionless particle (used to negate a limitation of the system bynanometer sized particles) to travel a distance equivalent to the widthof the laser beam. This will ensure that each particulate is hit by thelaser at least once. There will be a vortex created by the plate.However, the 1^(st) reflection off the reflective surface of theventilation duct will fill that vortex space with energy therebysterilizing it.

For this example, a laser beam of width 3 mm will be used.

The time that it takes a particulate to travel the width of this laserbeam is:

$T = {\frac{D}{V} = {\frac{3\mspace{14mu} {mm}}{0.147\mspace{14mu} {m/\sec}} = {\frac{3 \times 10^{- 3}\mspace{14mu} m}{0.147\mspace{14mu} {m/\sec}} = {0.0204\mspace{14mu} \sec}}}}$

Now, from the time that the particulate travels the width of the beam,the reflective plate must rotate the beam once around the circumferenceof the vent. Doing so will guarantee that no particulate will passthrough the “laser field” without being hit by the laser beam; asmentioned above. The refractive window must therefore rotate at avelocity (v) of:

$v = {\frac{D}{T} = {\frac{perimeter}{0.0204\mspace{14mu} \sec} = {\frac{4L}{0.0204\mspace{14mu} \sec} = {\frac{4 \times 0.3048\mspace{14mu} m}{0.0204\mspace{14mu} \sec} = {59.75\mspace{14mu} m\text{/}s}}}}}$

Continuing unit's yields:

v=59.75 meter/sec×revolution/1.2192 meter×60 sec/min⇒2940.5 rev/min(rpm)

Thus, for the maximum airflow that will be found in any square laminarventilation system, the field of laser energy created using a 3 mm beamin a 1 ft×1 ft square diameter ventilation duct with a reflective platethat is rotating at 3,000 rpm will impact approximately 100% ofparticulate.

Examples 1 and 2 above can be similarly employed for other cylindricalor square shaped chambers, or chambers of other shapes, to increase thelikelihood of particulate traveling at a given velocity to be impactedby an energy beam in a single rotation of the optical element. It willbe understood that although Examples 1 and 2 employ laminar flowexamples, higher linear speed velocities creating turbulent flows (suchas in laboratory exhaust plumes) can be similarly purified and/orsterilized through similar use of beam width, beam director rotationalvelocity, and linear velocity of a particle within a ventilation systemair stream.

All references cited herein are incorporated herein by reference intheir entirety. To the extent publications and patents or patentapplications incorporated by reference contradict the disclosurecontained in the specification, the specification is intended tosupersede and/or take precedence over any such contradictory material.

Many modifications and variations of this invention can be made withoutdeparting from its spirit and scope, as will be apparent to thoseskilled in the art. The specific embodiments described herein areoffered by way of example only and are not meant to be limiting in anyway. It is intended that the specification and examples be considered asexemplary only.

1. An air purification apparatus, comprising: a chamber comprising oneor more walls forming an interior volume, wherein at least one of thewalls comprises a reflective surface facing inwardly towards theinterior volume; a collimated light source configured to direct a beamof collimated light energy into the chamber; and a charge generationsystem configured to impart a charge to the one or more walls, to repelparticles contained within the interior volume from the one or morewalls.
 2. The air purification apparatus of claim 1, wherein the chargegeneration system is configured to impart a similar charge on theparticles within the interior volume.
 3. The air purification apparatusof claim 1, wherein the charge generation system is configured to imparta negative charge. 4-10. (canceled)
 11. An air purification apparatuscomprising: a chamber comprising one or more sidewalls forming an innercross-sectional area extended longitudinally along a longitudinal axisto form an interior volume, each sidewall comprising an inwardly-facingreflective surface; a collimated light source configured to direct abeam of collimated light into the chamber; and a beam redirectordisposed within the interior volume and configured to rotate through acomplete revolution about a rotational axis such that the beam ofcollimated light energy is redirected to form a field of collimatedlight energy extending across substantially an entirety of the crosssectional area of the interior volume and extending longitudinally alongthe longitudinal axis.
 12. The air purification apparatus of claim 11,wherein the chamber comprises a first end and a second end configured toallow air to flow through the chamber through the interior volume fromthe first end to the second end along the longitudinal axis.
 13. The airpurification apparatus of claim 11, wherein the collimated light sourceis a laser.
 14. The air purification apparatus of claim 11, wherein thechamber is cylindrical.
 15. The air purification apparatus of claim 14,wherein the beam redirector is disposed within an elbow of the chamber.16. The air purification apparatus of claim 11, wherein the beamredirector comprises an optic element with a surface comprising areflective material.
 17. The air purification apparatus of claim 11,wherein the beam redirector comprises an optic element with a refractivelens.
 18. The air purification apparatus of claim 11, wherein the fieldof collimated light energy has a substantially frustroconical shape. 19.The air purification apparatus of claim 11, wherein a portion of thereflective surface is oriented to be substantially non-parallel with thelongitudinal axis.
 20. The air purification apparatus of claim 19,wherein the reflective surface comprises one or more reflective grooves.21. The air purification apparatus of claim 11, wherein the field ofcollimated light energy is reflected by the inwardly-facing reflectivesurface to form one or more reflected energy fields extendinglongitudinally along the longitudinal axis.
 22. The air purificationapparatus of claim 11, further comprising an energy abatement devicepositioned within the chamber and configured to absorb the energy of thefield of collimated light energy.
 23. The air purification apparatus ofclaim 11, further comprising a controller configured to rotate the beamredirector about the rotational axis at a rotational velocitycorresponding to V/W, wherein V is the linear velocity of a particlewithin the chamber along the longitudinal axis, and W is the width ofthe beam of collimated light energy.
 24. An air purification apparatuscomprising: a chamber comprising: one or more sidewalls forming aninterior volume, the one or more sidewalls comprising one or moresurfaces facing inwardly towards the interior volume; and a firstopening and a second opening configured to allow air to flow through theinterior volume from the first opening to the second opening along alongitudinal axis; a collimated light source configured to direct a beamof collimated light energy into the interior volume of the chamber; abeam redirector disposed within the interior volume and configured torotate through a complete revolution about a rotational axis such thatthe beam of collimated light energy is redirected to form a field ofcollimated light energy extending across substantially an entirety of across sectional area of the interior volume during said revolution; anda controller configured to rotate the beam redirector about therotational axis at a rotational velocity corresponding to at least V/W,wherein V is the linear velocity of a particle within the chamber alongthe longitudinal axis, and W is the width of the beam of collimatedlight energy.
 25. The air purification apparatus of claim 24, whereinthe field of collimated light energy comprises a plurality of coplanarreflected beams.
 26. The air purification apparatus of claim 24, whereinthe field of collimated light energy extends longitudinally along thelongitudinal axis.
 27. The air purification apparatus of claim 24,wherein the collimated light source is a laser. 28-32. (canceled)